My research focuses on the structure of protons and neutrons, the buliding blocks of atomic nuclei.
A
photon incident on
a proton or a neutron causes a polarization or excitation of the
nucleon if the
wavelength is sufficiently small. Similar phenomena at much larger length scales are well known in
optics and atomic physics, when visible light interacts with matter.
In
contrast to such atomic systems, we have only a poor understanding of
the mechanisms responsible for the formation of nucleon excitions and
even the empirical
knowledge about the mass spectrum of light hadrons is rather
limited.
Photoinduced
mesons
production and Compton
scattering
on nucleons are powerfull tools to study nucleon resonances and
poalrizabilities. Presently new experiemts are performed at the photon
beam facilities A2 at
MAMI and Crystal-Barrel at
ELSA.
Hadron structure and spectroscopy with
high-energy muon and hadron beams are key aspects of the COMPASS experiment at
CERN.